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Astrophysics > Earth and Planetary Astrophysics

Title:
Physical constraints on the likelihood of life on exoplanets

Abstract: One of the most fundamental questions in exoplanetology is to determine
whether a given planet is habitable. We estimate the relative likelihood of a
planet's propensity towards habitability by considering key physical
characteristics such as the role of temperature on ecological and evolutionary
processes, and atmospheric losses via hydrodynamic escape and stellar wind
erosion. From our analysis, we demonstrate that Earth-sized exoplanets in the
habitable zone around M-dwarfs seemingly display much lower prospects of being
habitable relative to Earth, owing to the higher incident ultraviolet fluxes
and closer distances to the host star. We illustrate our results by
specifically computing the likelihood (of supporting life) for the recently
discovered exoplanets, Proxima b and TRAPPIST-1e, which we find to be several
orders of magnitude smaller than that of Earth.

Comments:

published in International Journal of Astrobiology; 31 pages; 3 figures